310 EIGHTEENTH REPORT ON THE STATE CABINET. 



GOMPHOCYSTITES TENAX (n. s.). 



Upper part of tlie body ventricose, somewhat rapidly attenuated below ; 

 principal aperture round, sub-central : the pyramid of plates which pro- 

 bably closed the orifice are unknown, leaving a margin of small unequal 

 plates. The plates forming the summit of the body are small, polygonal, 

 with surface strongly granulose. The arm plates appear to have been fur- 

 nished with tentacula, as in Apiocystites and others. 



Formation and locality. This species occurs in the Niagara group at 

 Lockport, N. Y. Collection of Col. E. Jewett. 



GOMPHOCYSTITES GLANS (n. s.). 



Body elongate, clavate, with the upper extremity extremely ventricose, 

 often more or less unsymmetrical and the summit unequally convex on 

 the upper side, and somewhat abruptly contracted below, and thence 

 gradually attenuate. Principal aperture subcentral : arms originating 

 close to that aperture, and curving in a spiral direction over the summit 

 and along the sides to the point of greatest expansion, or sometimes a little 

 below. 

 The specimens of this species are from one to three inches in length, 



with a diameter in the greatest expansion of less than half an inch to an 



inch and a half. 



The illustrations are of a large unsymmetrical specimen, and one of 



symmetrical form somewhat smaller. 



Formation and locality. In the limestone at Racine, Wisconsin. 



GOMPHOCYSTITES CLAYUS (n. s.). 



Body clavate, gradually expanding to the upper part which is elongate 



ovate, nearly or quite symmetrical, summit regularly convex : principal 



aperture at the apex, and essentially central. 

 Arms originating from one side of the central aperture, curving a little 



spirally downwards, and reaching below the apex a distance about equal 



to the greatest diameter of the body. 



Below the expanded portion, the body becomes obtusely pentagonal, a 

 feature but obscurely shown in the cast : base unknown. 



This species is very nearly symmetrical, and much more gradually ex- 

 panding from below to the greatest diameter, and less abruptly rounded 

 above ; while the arms have a more nearly vertical direction. 



It is possible that this may be only a modification in form of the G. 

 glans ; but among a considerable number of specimens of that species, I 

 have not observed gradations to this form ; and I therefore designate it as 

 a distinct species until it can be proved identical, or until I can determine 

 satisfactorily it's relations with the preceding species. 



Formation and locality. In the limestone at Racine, Wisconsin. 



